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INETD(8)		FreeBSD	System Manager's Manual		      INETD(8)

     inetd, inetd.conf -- internet super-server

     inetd [-d]	[-R rate] [configuration_file]

     inetd should be run at boot time by /etc/rc (see rc(8)).  It then listens
     for connections on	certain	internet sockets.  When	a connection is	found
     on	one of its sockets, it decides what service the	socket corresponds to,
     and invokes a program to service the request.  After the program is fin-
     ished, it continues to listen on the socket (except in some cases which
     will be described below).	Essentially, inetd allows running one daemon
     to	invoke several others, reducing	load on	the system.

     The options are as	follows:

     -d	     Turns on debugging.

     -R	rate
	     Specify the maximum number	of times a service can be invoked in
	     one minute; the default is	256.  If a service exceeds this	limit,
	     inetd will	log the	problem	and stop servicing requests for	the
	     specific service for ten minutes.	See also the wait/nowait con-
	     figuration	fields below.

     Upon execution, inetd reads its configuration information from a configu-
     ration file which,	by default, is /etc/inetd.conf.	 There must be an en-
     try for each field	of the configuration file, with	entries	for each field
     separated by a tab	or a space.  Comments are denoted by a "#" at the be-
     ginning of	a line.	 The fields of the configuration file are as follows:

	   service name
	   socket type
	   user[.group]	or user[:group]
	   server program
	   server program arguments

     To	specify	a Sun-RPC based	service, the entry would contain these fields.

	   service name/version
	   socket type
	   user[.group]	or user[:group]
	   server program
	   server program arguments

     For internet services, the	first field of the line	may also have a	host
     address specifier prefixed	to it, separated from the service name by a
     colon.  If	this is	done, the string before	the colon in the first field
     indicates what local address inetd	should use when	listening for that
     service.  Multiple	local addresses	can be specified on the	same line,
     separated by commas.  Numeric IP addresses	in dotted-quad notation	can be
     used as well as symbolic hostnames.  Symbolic hostnames are looked	up us-
     ing getaddrinfo().	 If a hostname has multiple address mappings, inetd
     creates a socket to listen	on each	address.

     The single	character "*" indicates	INADDR_ANY, meaning "all local
     addresses".  To avoid repeating an	address	that occurs frequently,	a line
     with a host address specifier and colon, but no further fields, causes
     the host address specifier	to be remembered and used for all further
     lines with	no explicit host specifier (until another such line or the end
     of	the file).  A line
     is	implicitly provided at the top of the file; thus, traditional configu-
     ration files (which have no host address specifiers) will be interpreted
     in	the traditional	manner,	with all services listened for on all local
     addresses.	 If the	protocol is "unix", this value is ignored.

     The service name entry is the name	of a valid service in the file
     /etc/services.  For "internal" services (discussed	below),	the service
     name must be the official name of the service (that is, the first entry
     in	/etc/services).	 When used to specify a	Sun-RPC	based service, this
     field is a	valid RPC service name in the file /etc/rpc.  The part on the
     right of the "/" is the RPC version number.  This can simply be a single
     numeric argument or a range of versions.  A range is bounded by the low
     version to	the high version - "rusers/1-3".  For UNIX-domain sockets this
     field specifies the path name of the socket.

     The socket	type should be one of "stream" or "dgram", depending on
     whether the socket	is a stream or datagram	socket.

     The protocol must be a valid protocol as given in /etc/protocols.	Exam-
     ples might	be "tcp" or "udp".  RPC	based services are specified with the
     "rpc/tcp" or "rpc/udp" service type.  "tcp" and "udp" will	be recognized
     as	"TCP or	UDP over default IP version".  This is currently IPv4, but in
     the future	it will	be IPv6.  If you need to specify IPv4 or IPv6 explic-
     itly, use something like "tcp4" or	"udp6".	 A protocol of "unix" is used
     to	specify	a socket in the	UNIX-domain.

     The wait/nowait entry is used to tell inetd if it should wait for the
     server program to return, or continue processing connections on the
     socket.  If a datagram server connects to its peer, freeing the socket so
     inetd can receive further messages	on the socket, it is said to be	a
     "multi-threaded" server, and should use the "nowait" entry.  For datagram
     servers which process all incoming	datagrams on a socket and eventually
     time out, the server is said to be	"single-threaded" and should use a
     "wait" entry.  comsat(8) (biff(1))	and talkd(8) are both examples of the
     latter type of datagram server.  The optional "max" suffix	(separated
     from "wait" or "nowait" by	a dot) specifies the maximum number of times a
     service can be invoked in one minute; the default is 256.	If a service
     exceeds this limit, inetd will log	the problem and	stop servicing re-
     quests for	the specific service for ten minutes.  See also	the -R option

     Stream servers are	usually	marked as "nowait" but if a single server
     process is	to handle multiple connections,	it may be marked as "wait".
     The master	socket will then be passed as fd 0 to the server, which	will
     then need to accept the incoming connection.  The server should eventu-
     ally time out and exit when no more connections are active.  inetd	will
     continue to listen	on the master socket for connections, so the server
     should not	close it when it exits.

     The user entry should contain the user name of the	user as	whom the
     server should run.	 This allows for servers to be given less permission
     than root.	 An optional group name	can be specified by appending a	dot to
     the user name followed by the group name.	This allows for	servers	to run
     with a different (primary)	group ID than specified	in the password	file.
     If	a group	is specified and user is not root, the supplementary groups
     associated	with that user will still be set.

     The server	program	entry should contain the pathname of the program which
     is	to be executed by inetd	when a request is found	on its socket.	If
     inetd provides this service internally, this entry	should be "internal".

     The server	program	arguments should be just as arguments normally are,
     starting with argv[0], which is the name of the program.  If the service
     is	provided internally, the word "internal" should	take the place of this

     inetd provides several "trivial" services internally by use of routines
     within itself.  These services are	"echo",	"discard", "chargen" (charac-
     ter generator), "daytime" (human readable time), and "time" (machine
     readable time, in the form	of the number of seconds since midnight, Janu-
     ary 1, 1900).  All	of these services are TCP based.  For details of these
     services, consult the appropriate RFC from	the Network Information	Cen-

     inetd rereads its configuration file when it receives a hangup signal,
     SIGHUP.  Services may be added, deleted or	modified when the configura-
     tion file is reread.

   IPv6	TCP/UDP	behavior
     If	you wish to run	a server for IPv4 and IPv6 traffic, you'll need	to run
     two separate processes for	the same server	program, specified as two sep-
     arate lines in inetd.conf,	for "tcp4" and "tcp6".

     Under various combinations	of IPv4/v6 daemon settings, inetd will behave
     as	follows:
     +o	 If you	have only one server on	"tcp4",	IPv4 traffic will be routed to
	 the server.  IPv6 traffic will	not be accepted.
     +o	 If you	have two servers on "tcp4" and "tcp6", IPv4 traffic will be
	 routed	to the server on "tcp4", and IPv6 traffic will go to server on
     +o	 If you	have only one server on	"tcp6",	only IPv6 traffic will be
	 routed	to the server.


     comsat(8),	fingerd(8), ftp-proxy(8), ftpd(8), identd(8), talkd(8)

     The inetd command appeared	in 4.3BSD.  Support for	Sun-RPC	based services
     is	modelled after that provided by	SunOS 4.1.  IPv6 support was added by
     the KAME project in 1999.

     Host address specifiers, while they make conceptual sense for RPC ser-
     vices, do not work	entirely correctly.  This is largely because the
     portmapper	interface does not provide a way to register different ports
     for the same service on different local addresses.	 Provided you never
     have more than one	entry for a given RPC service, everything should work
     correctly.	 (Note that default host address specifiers do apply to	RPC
     lines with	no explicit specifier.)

FreeBSD	13.0		       February	10, 2020		  FreeBSD 13.0


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